In the United States a mixture of sodium lactate (NaL) and/or potassium lactate and sodium diacetate (NaAc) is known as a method to prevent growth of Listeria monocytogenes in processed meats. It is also known to treat processed food, to use NaL or NaL/NaAc in combination with Nisin (a bacteriocin derived from Lactococcus lactis), Microgard (a Propionii), and Alta 2341 (a commercially available fermentation product of Pediococcus acidilactici).
Carnobacterium maltaromaticum is one species of a diverse group of bacteria that are classified as Lactic Acid Bacteria (LAB). LAB have been utilized for centuries in the food and dairy industries in the production of fermented foods. Important in this capacity is their ability to produce aromatic and flavor-enhancing compounds (Stiles and Holzapfel, 1997; Carr et al., 2002). LAB have been characterized by their ability to produce a variety of isomers of lactic acid from the fermentation of carbohydrates. Carnobacteria are distinct from Lactobacilli due their inability to grow on acetate agar at pH 5.6, while being able to produce virtually pure L(+)-lactic acid from glucose, and in their ability to ferment both glycerol and mannitol, properties that are unusual in lactobacilli (Holzapfel and Gerber, 1983; Shaw and Harding, 1984).
One of the methods by which C. maltaromaticum may inhibit potentially pathogenic bacteria is through the production of bacteriocins. Bacteriocins are ribosomally synthesized, low molecular weight antibacterial proteinaceous materials that are able to kill closely related bacteria (Klaenhammer, 1993). Bacteriocins have been shown to be produced by LAB isolated from beef, spoiled ham, as well as from French mold-ripened soft cheese (Jack et al., 1996; Herbin et al., 1997). Because bacteriocins are isolated from LAB from foods such as meat and dairy products, both LAB and bacteriocins have been consumed for centuries. The inhibitory substances produced from C. maltaromaticum have been shown to be bacteriocins by their susceptibility to proteolytic enzymes.
There is a continual need for new food preservatives bearing new and useful properties. Further, there is growing interest in replacing traditional “chemical” food preservatives with effective “natural” preservatives, especially those that inhibit pathogenic microorganisms. In this regard, considerable research has been conducted on bacterial peptides, e.g., bacteriocins, which are often heat stable and have antimicrobial activity.
Notwithstanding the usefulness of the above-described methods, a need still exists for enhanced preservation of processed food to control the growth and/or to eliminate bacterial contamination, particularly L. monocytogenes. 